While global average temperature has remained steady over the past 15 years, a visiting professor said at a talk Friday that there are warmer temperatures in store for us.

Shang-Ping Xie, University of California-San Diego climate, atmospheric science and physical oceanography professor, said his research indicated the decadal cooling of the Pacific Ocean seems to be a major cause of the current global warming hiatus. According to Xie, the cooling of the Pacific could not be linked to a carbon dioxide increase and is an example of enhanced climate variability.

“This led us to believe that the decadal cooling we saw over the past 15 years is largely due to natural variability,” Xie said. “If that is true, what’s going down is going to come up. So, when the pacific decadal isolation swings into a positive phase, we are going to see global warming coming back.”

Yuko Okumura, a research associate at the Institute for Geophysics in the Jackson School of Geosciences, organized Xie’s talk. Okumura said she thinks some people may still be skeptical about global warming because of the hiatus. According to Okumura, the natural variability caused by the interactions of the ocean and the atmosphere tends to overshadow the impact of human-caused climate change.

Judd Partin, a research scientist at the University’s geophysics institute who studies past climate change, said he thought Xie gave a great explanation of the hiatus in global warming. He said that, until the talk, he had not known sea surface temperatures can control
rainfall patterns.

Xie said the heat waves, warm temperatures and droughts seen in the southern United States seem to have resulted from the hiatus event because all of the precipitation and temperature patterns can be traced back to tropical Pacific cooling.